The QCD effective charge (Formula presented.) is an observable that characterizes the magnitude of the strong interaction. At high momentum Q, it coincides with the QCD running coupling (Formula presented.). At low Q, it offers a nonperturbative definition of the running coupling. We have extracted (Formula presented.) from measurements carried out at Jefferson Lab that span the very low to moderately high Q domain, (Formula presented.) GeV. The precision of the new results is much improved over the previous extractions and the reach in Q at the lower end is significantly expanded. The data show that (Formula presented.) becomes Q-independent at very low Q. They compare well with two recent predictions of the QCD effective charge based on Dyson–Schwinger equations and on the AdS/CFT duality.
|Number of pages||9|
|State||Published - Jun 2022|
Bibliographical noteFunding Information:
The authors thank D. Binosi, S.J. Brodsky, Z.-F. Cui, G.F. de Téramond, J. Papavassiliou, C.D. Roberts and J. Rodríguez-Quintero for their valuable comments on the manuscript. This work is supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, contracts DE-AC05-06OR23177 and DE-FG02-99ER41101.
© 2022 by the authors.
- running coupling constant
- spin structure
- strong interaction
ASJC Scopus subject areas
- Nuclear and High Energy Physics
- Astronomy and Astrophysics
- Physics and Astronomy (miscellaneous)